Comcast cable Internet service is currently marketed at 6Mbps and 8Mbps download speeds – very speedy indeed compared to DSL service that typically runs 1.5Mbps or less. There are rumors that Comcast will increase speeds again next year.

In the meantime Comcast apparently has built its system so robustly that it has excess capacity – bandwidth to spare. Now Comcast has developed “Powerboost,” patented technology that can soak up some of that excess capacity by using it to accelerate downloads. Here’s an article about Comcast and Powerboost. Forum posts at Broadband Reports suggest that download speeds can increase tremendously for the first thirty seconds or so, then drop back to normal. Thirty seconds is enough to download all but the biggest files, so the effect is to create the impression that the connection is flying all the time.

I didn’t know anything about it but my connection has been so perky that I went off to run some speed tests. The test results looked like a mistake:

30Mbps download speed! Whoosh! I did another test using a different test server:

Quite different, but still twice as fast as I expected. That seems to be the characteristic of this Powerboost trick – no guarantee, not necessarily consistent, just the possibility that some things will happen very, very quickly. Cool!